linux — security advisory

{
  "id": "a44c0d5d99d884695bd3053ceed64403ccb6fbf37efee701eb60c5df2295cddf",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2023-52843",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2023-52843",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: llc: verify mac len before reading mac header LLC reads the mac header with eth_hdr without verifying that the skb has an Ethernet header. Syzbot was able to enter llc_rcv on a tun device. Tun can insert packets without mac len and with user configurable skb->protocol (passing a tun_pi header when not configuring IFF_NO_PI). BUG: KMSAN: uninit-value in llc_station_ac_send_test_r net/llc/llc_station.c:81 [inline] BUG: KMSAN: uninit-value in llc_station_rcv+0x6fb/0x1290 net/llc/llc_station.c:111 llc_station_ac_send_test_r net/llc/llc_station.c:81 [inline] llc_station_rcv+0x6fb/0x1290 net/llc/llc_station.c:111 llc_rcv+0xc5d/0x14a0 net/llc/llc_input.c:218 __netif_receive_skb_one_core net/core/dev.c:5523 [inline] __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5637 netif_receive_skb_internal net/core/dev.c:5723 [inline] netif_receive_skb+0x58/0x660 net/core/dev.c:5782 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555 tun_get_user+0x54c5/0x69c0 drivers/net/tun.c:2002 Add a mac_len test before all three eth_hdr(skb) calls under net/llc. There are further uses in include/net/llc_pdu.h. All these are protected by a test skb->protocol == ETH_P_802_2. Which does not protect against this tun scenario. But the mac_len test added in this patch in llc_fixup_skb will indirectly protect those too. That is called from llc_rcv before any other LLC code. It is tempting to just add a blanket mac_len check in llc_rcv, but not sure ",
    "evidence": "osv:DEBIAN-CVE-2023-52843",
    "products": [
      {
        "name": {
          "value": "linux",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.64-1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "6.1.27-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "6.1.37-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "6.1.38-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "6.1.38-2",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "6.1.38-2~bpo11+1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "6.1.38-3",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "6.1.38-4",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "6.1.38-4~bpo11+1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "6.1.52-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "6.1.55-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "6.1.55-1~bpo11+1",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "linux",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.8-1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "linux",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.8-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2023-52843",
      "aliases": [
        "DEBIAN-CVE-2023-52843"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "6.1.64-1"
                }
              ]
            }
          ],
          "package": {
            "name": "linux",
            "purl": "pkg:deb/debian/linux?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "6.1.27-1",
            "6.1.37-1",
            "6.1.38-1",
            "6.1.38-2",
            "6.1.38-2~bpo11+1",
            "6.1.38-3",
            "6.1.38-4",
            "6.1.38-4~bpo11+1",
            "6.1.52-1",
            "6.1.55-1",
            "6.1.55-1~bpo11+1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-52843.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "6.6.8-1"
                }
              ]
            }
          ],
          "package": {
            "name": "linux",
            "purl": "pkg:deb/debian/linux?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-52843.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "6.6.8-1"
                }
              ]
            }
          ],
          "package": {
            "name": "linux",
            "purl": "pkg:deb/debian/linux?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2023-52843.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-26T18:03:08.208865543Z",
      "provider": "osv",
      "upstream": [
        "CVE-2023-52843"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2023-52843"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2023-52843",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 457819,
  "published_at": "2024-05-21T16:15:21.583+00:00"
}